Evaporative or "swamp" coolers are generally rectangular box like structures mountable on the roof of a building. The cooler usually includes corners, top and bottom frame members with porous water absorbing material such as excelsior forming the vertical walls thereof. A centrifugal or "squirrel" cage fan is usually provided to draw air in through the wet porous material and channel the same through the cage to a duct conveying the air into the building.
In order to cool the air, water is provided to drip from the top of the cooler by a manifold through the porous material ending at the bottom of the cooler in a dish or reservoir for reuse.
Various types of pumps and couplings have been employed to move the water upward from the reservoir to the manifold for distribution into the porous material. Some of such water pumps were powered by small motors separate from larger motors used to drive the centrifugal fan. These smaller motors often malfunctioned and required repair. Further, some of the water pumps in the past did not include filtration means and became clogged and would not function.